Edward salomon berglund



x'. E. S. BERGLUND. EXTRACHUN OF LEAD. APPLICATION HLED MAH- H. IEHH.

1 ,306,942. Patented June 17, 1919.

INVE NTOR -SBe-rgl u/nc BY 66%. 1M

ATTORNEY UNITED STATES PATENT OFFICE.

EDWARD SALOMON BEBGLUND, OF TROLLHKTTAN, SWEDEN, ASSIGNOR TO SVEN HULDT, OF STOCKHOLM, S\VEDEN.

EXTRACTION OF LEAD.

Application filed March 11,

To all whom. it may concern Be it known that I, llowxuu SALOMON Bnncnunu, residing at 'lrollhiittan, Sweden, have invented certain new and useful Iniprovcments in the Extinction of Lead, of which the followin is a specification.

For extracting end in a rcverberatory furnace, the so called roastingandreact on method or in some cases the precipitatmg method, in which the lead is extracted by smelting the unronsted ore together with metallic iron, hitherto has been employed.

-In a common reverbemtory furnace, heated by means .of coal firing, andin which the roasting and reaction method is performed, it is possible to make the (lame, heatingthe furnace and the charge, reducing, .mdifl'ercut or oxidizing, as may be dean-ed, even although the atmosphere has a free admission to the furnace chamber. The furnace gases in this case pneventthe lead, be ng extracted during the reaction, from be ng oxidized, so that the result of the smelting operation will be reduced lead.

However the roasting and reaction method in a common reverberatony furnace is only .employahle for ores rich in lead, in view of the fact that the method owing to the considerable '(SOIISIIIHPtlOfl of fuel would he uneconomioal tonsew th lenn ores. Moroovcr only such ores are employable, which contain less than five per cent. silicic acid, as the silicic acid together with lead nxid forms lend silicate, and prevents the desired reaction for the reduction of lead.

Further in the usual method of extracting lend the temperature must be maintained within certain limits in the furnace, so that the charge does not smelt, as in such case the reaction is rendered more diilicult, and moreover heavy losses of load, owing to the volutilizing of lead occur at high temperatures. In said method therefore only per cent. of the amount of lend contained in the charge can be extracted. For extractihg the remaining amount of lead oxid contained in the smelted residue, said residue must be subjected to n re-smelting operation in a shaft furnace.

Even in extracting lead accolding to the precipitating method by means of metallic iron the necessary high temperature results in heavy losses of lead.

The result is the same when employing roasted lead ore or residues containing lead, according to the roasting and reaction Patented June 1 7, 1919.

1918. Serial No. 221,5s2.

method, the reduction with carbon necessitating so high temperatures, that the losses of lead owin to the volatilizntion of lend are cunsidcrn le.

Moreover said losses of lead involve it great danger for poisoning of the employees.

The methods for extracting lend hitherto used have thus been limited to certain, suitable ores, and it has not been possible to extract all of the lead contained in said ores, by the said methods. 7

The present invention has for its object to avoid the inconveniences, connected with the methods hitherto employed for extracting lead, and to utilize any material contaming lead, and thereby to extract, practically asking all of the lead contained in the e arge. The invention consists in treating the material, containin lead, which of course is mixed with an stances necessary for the reactions required, by means of electric heat at a temperature which is so high that the change is completely smelted, whereby the access of the atmosphere to the smelting chamber is prevented, and the vapors, arising at the smelting operation, are condensed.

B employing such high tem ratures, in per mnin the method that't 0 char e is completed y smelted, racti'cnlly spea :ing all of the lead contain in the charge, is extracted in one single smelting operation, and by the combination of the smelting operation with a condensation of the escaping vapors. containing lead, no substantial losses of lead result. Thus it is possible to choose that method of treating the ore, which is most suitable for the charge in question.

For heating [casted ore or oxidized producl's containing lend, the charge is mixed with the summit of carbon necessary for the reduction, and also, if necessary, with a suitable amount of slag producing substances.

A mixture of unroasted and roasted ore may be smoltcd according to the reaction method, also unroasted ore, mixed with! products, containing lend oxid, whereby even in these cases producing substances mnv be added. if necessary.

Uni-casted ore muy be snielted alone mixed with metallic iron or with iron ore and carbon.

It has been shown that if the known roasting and reaction method be carried out in an electric furnace, constructed in accordance with the common rcverberatory furnaces employed for extracting lead, onl a small amount of metallic lead is obtained. in such an electric furnace the reduced lead is not protected by a sullicient amount of gases, as in the common I'CVOK'bOK'RLOIy furnace, and therefore thelcad will be oxidized to lead oxid at the time of its formation. The result therefore will be a mere roasting of the ore, after which the ore will slag or smelt to a more or less rich mass, containing lead oxid.

The drawing shows an embodiment of a construction for carrying out the present invention. Figure l is a longitudinal section and Fig. 2 a transverse section on the line ab in Fig. 1 of a smelting furnace according to the present invention.

1 indicates the electric smelting chamber, 2, 2, the electrodes between which there is produced an electric light are, 3 a feed hop per and 4 a feed screw for continuously introducing the material, containing lead. 5 indicates a tapping opening for slag, and 6 a channel, arran ed as a fluid seal, from which the reduced ead is drawn oil. 7 indicates a condensing device for the condensation of vapors, and 8 indicates the exhaust conduit for the noncondensed vapors and gases escaping from the condenser 7, said conduit extending down into a liquid seal 9, from which an escape pipe 10 leads to the atmosphere or to any other place, where the escaping vapors and gases may be consumed if'desired.

The arrangement is such, that the smelting chamber 18 shut 05 from the atmosphere at the place 4 of introduction as well as at the place 6 for drawing oil the lead, and at the point of esca e 8, 9, 10 of the non-condensed vapors. t the start of the process the drawing ofi' place 6 is filled with 'smeltcd lead and the escapes 8, 9, 10 with fluid. The introduction of material containing lead is preferably thereafter performed continuously, whereby the material is introduced on the bottom of furnace chamber 1, where the reactions take place and the material is fused simultaneously with the extraction of metallic lead. As the access of air is shut oil from the furnace chamber as mentioned, no oxidation of the extracted lead takes place, but said lead runs down the inclined furnace bottom to the channel 6, where the lead serves as a liquid seal, from which the lead may be drawn ofl' throu h the opening 11. The temperature in t e furnace chamber is maintained so high, that the charge completely smclts. The amount of lead, which thereby possibly vaporizes, will not be lost, as in hitherto used methods, but is condensed in the condenser 7. By

this means vapors and gases produced in the smelting chamber, may be drawn oil without dilliculty in such a nmnner, that [l e non-condensed gases and vapors, escaping through the conduit 10, are practically free from lead. By means of the liquid seal 9 the gas flow from the smelting chamber 1 may be regulated as desired.

Having now particularly described my in- \ontion, and in what manner the same is to be performed, I claim as my invention:

1. The method of extracting lead, consisting in smelting a charge, containing lead, by means of electric heat, excluding access of air, drawing oil' in liquid form, separately, the slag and a part of the molten lead from the furnace chamber, and condensing the lead vapors carried by the escaping vapors and ases.

2. The metho of 'extractin sisting in continuously introducing a charge, containing lead, in an electric hermetically closed furnace chamber, smelting said charge by means of electric heat, drawing off the liquid extracted'lead, excluding access of air, and condensing the escaping vapors containing lead.

3. The method of extracting lead, consisting in smelting a charge, containing lead, by means of an electric arc, excludin air from the furnace chamber, drawing 0 one part of the lead-in liquid form through a liquid seal, and condensing the lead vapors from the gaseous roducts of the reaction.

4. A method 0 extracting lead, consisting in treating the charge containing lead by means of electric'heat at such a high temperature that the charge and slag-forming material suitable for the process are completely smelted, excludingaccess of air from the furnace collecting the liquid extracted lead in the furnace chamber, and condensing the escaping lead vapors.

5. A method of extracting lead, consisting in continuously introducing a charge containing lead into a furnace chamber, exposing said charge to such high temperature y means of electric heat, that the charge and the slag material contained therein are completely smelted, gathering the liquid, extracted lead in the furnace chamber so that it constitutes a seal, conducting the escaping lead vapors away from the chamber, condensing such vapors, and carrying off the non-condensed vapors without admission of air.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EDWARD SALOMON BERGLUND.

\Vitnesses:

l-lnoo lnNnAM, Vnnxnn Svanruson.

Copies of this patent may be obtained for five cents each, by addressing the "Commissioner of Patents Washington, D. 0.

lead, con-' 

